Electron discharge device



Jan. 12, 1937. v R. A. HEISING I 2,057,529

ELECTRON DI SCHARGE DEVICE Filed Feb. 20, 1954 2 Sheets-Sheet 2 /N VE N TOR By RAHEISING WILD/z, 6. ArroR/vgr Patented Jan. 12, 1937 SA'EEF PTN'E' @FFIQE ELECTRON DISCHARGE DEVICE Raymond A. Heising, Summit, N. 5., assignor to Bell Telephone Laboratories,

Incorporated,

This invention relates to electron discharge devices and more particularly to such devices wherein the control electrode and the anode are shielded or screened from each other.

One object of this invention is to effectively shield the control electrode in an electron discharge device from the anode.

Another object of this invention is to simplify the structure and to reduce the number of elements in electron discharge devices of the shielded control electrode type.

In one embodiment of this invention, an electron discharge device comprises an anode, a control electrode, and a cathode disposed between the anode and the control electrode.

In accordance with one feature of this invention, the cathode is so designed and positioned as to shield the control electrode and anode from each other. In one form, the cathode may comprise an electron emitting portion confined between the longitudinal extremities of the control electrode, and non-emitting portions extending beyond the longitudinal extremities of the control electrode.

In accordance with another feature of this invention, metallic members, which may serve as supports for the cathode and may be electrically connected to the cathode, are provided on opposite sides of the cathode and disposed in a surface extending between juxtaposed or aligned portions of the control electrode and the anode to increase the shielding between the anode and the control electrode.

In accordance with a further feature of this invention, the cathode and the metallic members are arranged on an arcuate boundary about either the control electrode or the anode to insure highly effective shielding between the control electrode and the anode.

The invention and the features thereof will be understood more clearly and fully from the following detailed description with reference to the accompanying drawings in which:

Fig. 1 is a perspective view of an electron discharge device illustrative of one embodiment of this invention, portions of the enclosing vessel being broken away to show the electrodes more clearly;

Fig. 2 is a diagrammatic view illustrating the relative positions of the electrodes in the device shown in Fig. 1;

Fig. 3 is a side view in elevation of the electrodes of the device shown in Fig. 1;

Fig. 4 is a perspective view of a cathode and shield structure which may be substituted for the cathode and shield structure shown in Fig. 1 in accordance with this invention, wherein the shield comprises mesh screens;

Fig. 5 shows a modification of the shield members and the cathode which are arranged in an '6 arcuate boundary in accordance with this invention;

Fig. 6 is a diagrammatic view showing the relative disposition of the three electrodes in a device embodying a cathode-shield structure of the form 10 shown in Fig. 5;

Fig. '7 is another diagrammatic view wherein the cathode and shield members are arranged in an arcuate boundary partly encompassing the anode;

Fig. 8 is a perspective view similar to Fig. 5, in which the shielding members are arcuate mesh screens;

Fig. 9 illustrates another modification in which the cathode and shielding members are formed of a continuous element;

Fig. 10 is a perspective view of an electrode assembly illustrative of another embodiment of this invention wherein the cathode and shield members are disposed in a cylindrical boundary completely encircling the control electrode, a portion of the anode being broken away to show the other electrodes more clearly;

Fig. 11 is a plan view of the stem of Fig. 10 on the line ll-ll showing the disposition of the supports thereon; and

Fig. 12 is a view in elevation of the electrode assembly shown in Fig. 10.

The electron discharge device illustrated in Fig. 1 comprises an evacuated enclosing vessel 10 which is suitably secured, as by cement, to a base II. The base II has a plurality of terminal prongs l2 thereon through which electrical connection may be made between the electrodes of the device and an external circuit. The enclosing vessel It is provided with a reentrant stem I3 terminating in a cross-shaped press M. A rigid support or wire [5 is embedded in one of the arms of the press I 4 and has mounted thereon a lateral metallic member I 6 which has secured thereto two spaced parallel wires or rods I! constituting the control electrode of the device. The control electrode is electrically connected to one of the terminal prongs I2 by a conductor !8 sealed in the stem l3 and connected to the wire I5.

A rigid support or rod I9 is embedded in the opposite arm of the press and carries a fiat, metallic plate 20 which serves as the anode of the device. As shown more clearly in Figs. 2 and 3, the anode 20 is parallel to a plane common to the coupled together by a metallic member 23 which by conductors 2i.

may be a channel-shaped band crimped' or otherwise secured to the ends of the wires. A pair of wires .24 supported between the press and the metallic member 23 are disposed in the same plane as the wires 22 and these wires serve as the cathode or emitting electrode of the device. The wires 22 have portions between the longitudinal extremities of the anode 2i and control electrode i1 which'may be coated with a thermionically active material, for example, barium and strontium oxides, as shown at 25 in Fig. 1. The wires 22 may be electrically connected together and to one of the terminal prongs l2 by conductors 26, and the end wires 22 may be electrically connected to each other and to another of the terminal prongs i2 The circuit for the cathode heating current, then, includes the conductors 21, wires 22, metallic member 23, wires 22, and conductors 26. Preferably the conductors 2? are connected to the negative terminal of the heating current source.

As shown clearly in Fig. 2, the cathode wires 2% are disposed in alignment with the control electrode wires i i. Preferably the wires 22 and 2d are spaced a distance commensurate with the diameter of the wires 22 and 24, for example, two times the diameter of the wires 22. In order to obtain a large amplification factor, the control electrode ii is preferably positioned close to the cathode wires 24 and the anode 29 is widely spaced from the cathode wires 22.

The cathode wires 24 and the cathode supporting wires 22 serve as a screen between the anode and the control electrode and thereby shield the control electrode from any varying potential on the anode. As is apparent from Fig. 2, the wires 22 and 22 form a shield extending lat- .erally beyond the anode 2! and control electrode I1, and as is apparent from Fig. 3, the wires 22 and 2 3 form a shield extending longitudinally beyond the anode 2i? and control electrode H. Preferably the wires 22 and 2dextend into the press an appreciable distance so that they shield the rod l5 and wire i8 from the rod i9 and wire 2!.

Although the cathode 22 has been shown and described as of the directly heated filament type, it may, of course, be of the indirectly heated equipotential type.

In Fig. 4, two U-shaped frames 28 are supported from a press 25! by supports or rods and are interconnected at the upper end by a metallic member 23. Each of the frames 22 has mounted thereon a fiat mesh screen 3 i, the screens and frames being disposed in a common plane. A pair of parallel wires 24 forming the cathode are disposed between the inner arms of the frames 23 and parallel to the screens 3 i, the wires 2d being embedded in the press at one end and secured to the metallic member 23 at the other end. Preferably the wires 26 are spaced closely adjacent each other and the inner arms of the frames 23 to form a highly effective screen. The wires 24 may be coated with a thermionically active material, as indicated by the portions 25. The wires 24 are electrically connected together by conductors 26 and the frames 23 are electrically connected together by conductors 2?. The cathode and screen assembly shown in Fig. 4 may be utilized in an electron discharge device of the general construction indicated in Fig. 1, and may be positioned between an anode 2i; and control electrode l l in substantially the same relation as indicated in Figs. 2 and 3.

Fig. 5 shows another modification of the oathode-screen assembly which includes a'press 28 in which bent supports or rods as are embedded. Each of the supports or rods 34- has secured thereto, by welding, an arcuate channel-shaped metallic member 35 which is secured, as by crimping or welding, to one end of a plurality of rigid parallel Wires or rods 36. V The wires or rods 35 are spaced at the other end by an arcuate metallic member 37 which is secured to the wires or rods in any suitable manner. A U-shaped filamentary cathode 38, having portions 25 coated with a thermionically active material, is Dositioned between the innermost wires or rods 36 and is secured at one end to the metallic member 3'1 and is supported from the press 29 at the other end by a rigid support or wire stub iii. The

side arms of the cathode, preferably, are parallel to the wires or rods 36. The heating current for the cathode may be supplied through a circuit including a conductor M connected to the support or stub 52, the cathode 33, member 31, wires n or rods 36, supports 3-4, and conductors 2? connected to the supports 34. Preferably the wires or rods 36 are connected through the conductors 21 to the negative terminal or" the source of cathode heating current. It will be understood, of course, that although the cathode has been illustrated" as of the filamentary type it may be of the heater type. The side arms of the cathode 38, and the Wires or rods 36 are positioned closely adjacent and are spaced a distance preferably not more than two times the diameter of the wires or rods 36.

As illustrated in Fig. 6, the cathode 38 and the wires or rods 38 are arranged in an arcuate boundary partly encompassing the control electrode ii, the side arms of the cathode 38 being disposed parallel to and in alignment with the control electrode wires. This arrangement increases the shielding of the control electrode from the anode. Preferably, the cathode 38 and wires or rods 35 extend materially beyond the longitudinal extremities of the control electrode I! and anode 29, substantially as shown in Fig. 3.

As illustrated in Fig. 7, the cathode 38 and wires or rods 36 may be arranged in an arcuate boundary partly encompassing the anode 20.

A modification of the cathode-screen assembly shown in Fig. 5 is illustrated in Fig. 8 and comprises arcuate mesh screens 43 which are mounted on U-shaped frames 44 supported from the press 29 by bent wires 34. The screens 43 and cathode 38 are arranged in an arcuate boundary and may be positioned, as illustrated in Figs. 6 and '7, to partly encompass either the control electrode H or the anode 2E].

In a further modification of this invention shown in Fig. 9, the cathode-screen assembly comprises a press 29 having embedded therein two upright supports or rods 45 which carry a pair of spaced insulating members 46 and 41. The insulating members 46 and 41 carry a plurality of bent hooks '48 on which .'a continuous length of wire or ribbon 49 issupported. 'The ends of thewire 49 are securedto the'upright supports or rods 45 so that the 'latter serve as leading-in conductors;

The central sections of the wire 59 such as 50, maybe coated with athermionically active material, such as barium and strontium oxides or otherwise rendered thermionically active. The assembly shown in Fig. 9, maybe associated with a control electrode and anode substantiallyas illustrated in Figs. 2 and 3, the insulating members preferably being positioned beyond the longitudinal extremities of the control electrode and anode so that :the control electrode is shielded both "longitudinally and laterally from the anode.

'In the embodiment of this invention shown in Figs. 10, 11, and 12, an electrode assembly comprises a cross-shaped press having pairs :of arms 5i and 52 disposed at substantially right angles to-each other; An uprightsupport or rod 53 is embedded in each of the arms 52 and secured to oppositely disposed flanges 54 on a cylindrical anode 55. The ends of the rods are secured to the arms 56 of an insulating plate or member 51.

A linear metallic rod 58 coaxial with the anode 55 is embedded in the press at the intersection of the arms 5| .and 52 and serves as the control electrode.

A plurality of inverted J-shaped supporting members or wires 59 are embedded, one in each of the arms 5| and 52 of the press, the members being bent and arranged in a substantially cylindrical boundary as shown in Fig. 11. An equal number of elongated U-shaped members 60 is supported from the insulating member 51, the members Bil likewise being bent and arranged in a substantially cylindrical boundary coaxial with the boundary including the members 59. A continuous filamentary cathode BI is suspended between the members 59 and 60 and comprises a plurality of V-shaped sections arranged in a cylindrical boundary coaxial with the control electrode 5B and the anode 55. Preferably, only the portions of the cathode sections between the longitudinal extremities of the control electrode are rendered thermionically active, for example, by coating with barium and strontium oxides. The heating current for the cathode may be supplied through conductors 62 and 63 each of which is connected to two oppositely disposed J-shaped members 59.

The cathode 6! and the supporting members 58 and 65 form a cylindrical screen between the control electrode 58 and the anode 55 and which extends materially beyond the ends of the anode 55 and the free end of the control electrode 58, and thereby shields the control electrode from the anode. Preferably, the arms of the members 59 embedded in the press extend into the press for a relatively long distance to shield the portion of the rod 58 embedded in the press and the leading-in conductor 64 secured thereto from the anode supporting rods 53 and the leading-in conductor 65 secured thereto. The other arm of each of the members 59 preferably extends downwardly to or beyond the plane of the top of the press.

Although a number of specific embodiments of the invention have been illustrated and described, it will be understood, of course, that modifications may be made therein without departing from the scope and spirit of this invention as defined in the appended claims.

What is claimedis:

'1. An electron discharge device comprising an anode, a control electrode, a cathode between said anode and said control electrode, said control electrode and cathode having aligned wire portions and said anode having portions in alignment with said cathode and control electrode, and shield members adjacent said cathode and having portions beyond the lateral extremities of said control electrode, said shield members being disposed in a surface extending between alignedportions of said anode and control electrode.

2. An electron discharge device comprising an anode, a control electrode including a pair of parallel wires, a cathode positioned between said control electrode and said anode and including a pair of parallel wires each of which is parallel to and in alignment with a corresponding one of said first mentioned parallel wires, and shielding means laterally adjacent said cathode.

3. An electron discharge device in accordance with claim 2, in which said cathode and said shielding means extend beyond the longitudinal extremities of the anode and the control electrode wires.

4. An electron discharge device comprising a pair of cold electrodes one of which includes a plurality of wires disposed in a plane, a cathode positioned between said cold electrodes and including wires in alignment with said first wires, and a plurality of metallic elements disposed laterally adjacent and on opposite sides of said cathode wires, said elements being electrically connected to said cathode and extending beyond the extremities of one of said electrodes.

5. An electron discharge device comprising a flat anode, a control electrode including a plurality of wires disposed parallel to each other and in a plane parallel to said anode, a plu rality of shield members, and a cathode including a plurality of parallel wires disposed between said shield members, said shield members and said cathode being disposed in a plane extending between said anode and the control electrode wires and parallel thereto, the cathode wires being in alignment with corresponding control electrode wires.

6. An electron discharge device comprising an anode, a control electrode, a cathode disposed between said anode and said control electrode, and metallic mesh screens later-aly adjacent said cathode and having portions beyond extremities of either of said anode for said control electrode.

'7. An electron discharge device comprising an anode, a control electrode including a plurality of wires, a cathode positioned between said anode and said control electrode, said cathode having portions in alignment with said wires, and wire mesh screens electrically connected to said cathode and positioned laterally adjacent the cathode portions.

8. An electron discharge device comprising a fiat anode, a control electrode including a plurality of parallel wires disposed in a plane parallel to said anode, a cathode including parallel wires in alignment with corresponding wires of said control electrode, and a plurality of mesh screens on opposite sides of the cathode wires and electrically connected thereto, the cathode wires and said screens being disposed in a surface extending between said anode and said control electrode.

9. An electron discharge device comprising an anode, a control electrode, a pair of frames disposed between said anode and said control electrode, wire mesh screens attached to said frames, a metallic member carried by said frames, and a cathode mechanically and electrically connected to said metallic member and disposed between said screens.

10. An electron discharge device comprising a pair of cold electrodes, a cathode between said cold electrodes, and metallic supports electrically connected to said cathode, said cathode and said supports being mounted in an arcuate boundary.

11. An electron discharge device comprising a pair of cold electrodes, a cathode positioned between said cold electrodes, and metallic shield members laterally adjacent and on opposite sides of said cathode, said cathode and said shield members being mounted in an arcuate boundary extending about one of said cold electrodes.

12. An electron discharge device comprising a pair of cold electrodes, one of said electrodes including a plurality of parallel wires, a cathode including arcplurallty of parallel wires disposed between said cold electrodes and in alignment with said electrode parallel wires, and shield members laterally adjacent and on opposite sides shield members, said cathode and said shield members being mounted in an arcuate boundary extending between said cold electrodes and about one of said cold electrodes.

RAYMOND A. HEISING. 

